wrong subform total

[Guest]

I have a subform called "InvoiceDetailssubform" and a main form called
"invoices details"
in the subform there is a field Expenseitemamount
so to get total of this field ,i have places a text box in the footer of the
subform , which i called it "Expense Totals"
now i want to get this figure for each record of the form " invoices
details" but unfortunatley am i getting wrong figure , i get the total amount
of all records in the source table of the subform .
although i am using the same way in another main and subform , and getting
correct results.
what could be the problem, how can i make it to show only total amount of
the subform records the belongs to the current main form record only.

( note: the subform is showing the correct number of records, it is not
showing all records in the source table.)

 

[Guest]

What do you have in the the ControlSource of the Sum text box?

Is it

=Sum([Expenseitemamount])

 

[Guest]

Is it

=Sum([Expenseitemamount])

yes , exactly.

and , the source for the field that i want it to show the result is this:

=[InvoicedetailsSubform].Form![Expense Totals]

but is showing the grand total for all of the records in the source table,
not only those which belongs to the current record of main form , as it is
acutlly showing(the subform is showing correct no of records).